MADEEPOEA. 33 



7. Madrepora attenuata. (PI. XXXV. figs. C, D.) 



Corallum slender, arborescent, 24 cm. or more in height. Main branches or stems (?) 

 1"2 cm. thick, gradually attenuate, giving rise to numerous branches and branchlets at an 

 angle of 30° to 40°, but occasionally the angle is wider ; the branches are usually simple, 1'5 

 to 11 cm. long, the longer ones being 5 to 7 mm. thick and slowly tapering. Axial corallites 

 2 mm. diameter, 1 to 2" 5 mm. exsert, wall porous and a little thickened, strongly striate, 

 the strise echinulate; star well developed, the primary septa subequal and often nearly 

 meeting together in the middle line, the second cycle also well developed. Radial corallites 

 spreading and distant, usually 2 mm. apart, nariform, often with a hooked lip, labellate or 

 tubular with an oblique aperture, varying in length from 2 to 4 mm., diameter 1*5 mm., 

 little variable ; the wall is moderately thick and very firm, becoming shorter and more 

 verruciform below. A few longer tubular corallites with round aperture occur near the apex 

 of the branches, some of which bear buds and indicate the position of new branchlets. Star 

 not very distinct, the directive septa are well developed, but the remaining primaries and 

 those of the second cycle are usually narrow. Corallum rather porous near the apex, 

 rapidly becoming denser below, surface dense, closely clothed with fine echinulations 

 throughout ; wall substriate or echinulate in longitudinal rows. 



West Indies. 



a-j. West Indies. Purchased. 43. 2. 10. 70 to 74 & 93. 4. 7. 142 to 146. (Types.) 



b. Colony massive, with irregular or mammiform elevations in place of proper branches. 



8. Madrepora cyclopea. 



Madrepora cyclopea, Dana, Zoophytes, p. 439 ; Eathbun, Proc. U.S. Nat. Mus. 1887, vol. x. p. 15. 

 Madrepora cycloptera, M.-Edwards & Haime, Coralliaires, t. iii. p. 161. 



Dana's description, taken from worn specimens, is as follows : — " Very broad foliate and 

 ponderous, fronds spreading, lobed, 3 to 6 inches thick and 6 feet or more broaxl, with large 

 rounded, remotely scattered knobs, 2 to 3 inches thick. Corallum above having calicles 

 crowded." The species is not figured and has not been recorded by subsequent investigators. 



The following description is taken from two specimens in the British Museum, which 

 appear to be referable to this species : — Corallum consisting of extremely massive, digitate 

 fronds about 1-8 m. across. Digitiform lobes rounded and gradually tapering to a 

 relatively slender apex; they are sub-reniform in section about the middle of a lobe; 

 diameters at a point about 40 cm. from the apex, 14 by 10 cm. The superior surface is 

 covered with irregular tubercles, those on the lobes becoming arranged chiefly in two series, 

 one near each lateral border; they are 2 to 5 cm. broad and about as high as broad, 

 occasionally conical, with a prominent central corallite, which, however, does not diflfer in 

 size or thickness from the others. Prominent corallites crowded, tubular, with a firm and 

 moderately thick wall; aperture usually round, rarely oblique. Length 1 to 6 mm., diameter 

 1-5 to 2-5 mm.; average about 2 mm. diameter and 4-5 mm. long. Scattered between the 



